Purpose: According to the trend of the global burden of disease, in the future our society is expected to face with gradually increasing problems related to mental health and the demand for the various types of quality mental health facilities. This study investigates whether the accreditation of Mental health facilities serves as a building evaluation tool, and contribute to environmental welfare of the mentally ill. Methods: The facility assessment items related to architectural design are extracted through the analysis about the accreditation program of KOIHA. Extracted items should review if they comply with the relevant regulations, and establish building design standard. Results: This study shows that the accreditation of KOIHA can certify psychiatric hospitals meet the legal requirements, the minimum standard of facilities. But it is not the evaluation of environmental quality. It is difficult to assess the quality of facility in terms of architectural design, because it has no specific standards or the level of assessment. Implications: The accreditation for mental health facilities should be able to provide the right and opportunity to choose a more quality facility for the customer. The introduction of a certification system for the evaluation of environmental quality is required in order to overcome the limitations of the accreditation of KOIHA. Development of design guidelines for mental health facilities that are the basis for certification should be also followed.